1. Field of the Invention
The invention relates to a device for simultaneously or sequentially carrying out chemical reactions.
2. Description of the Related Art
In many series of chemical experiments, it is necessary to bring a number of reaction partners to reaction with a predetermined substance and evaluate, further process or analyze the respective reaction products. In other series of chemical experiments, it is necessary to bring a predetermined substance into contact successively with a series of reagents and evaluate, further process or analyze the respective reaction products. Such series of experiments are always time-consuming and represent monotonous, routine work. Therefore, one tries to automate such series of experiments with the aid of suitable devices or apparatuses.
Particularly in biochemistry, such series of experiments, especially of the second type, must be performed frequently. An example of this is oligonucleotide synthesis, which has achieved great: significance for a number of molecular biology techniques. Particularly worth mentioning are the methods of PCR poly chain reaction) and DNA sequence analysis, in which so-called "primers," which are short, individual strands of DNA having a length of approximately 16 to 20 nucleotides, are used.
A further problem is that the substances and their reactions are often very expensive. Therefore, one will attempt to make do with the smallest possible quantities.
Particularly in sequence analysis with so-called "primer walking" methods, in which the primer sequence for the next sequencing step is read out of the newly-determined sequence and used for synthesis of a new primer, only very small quantities of oligonucleotides, approximately in the pMol range, are used for the actual determination of sequence.
There are numerous commercially-available apparatuses with which syntheses can principally be performed in series of experiments of the first or second type, and particularly oligonucleotide syntheses. However, all of these apparatuses are designed for substance quantities of more than 40 nMol, that is, for quantities that are more than 1000 times larger than needed. In many cases the high price of primer syntheses prevents widespread application of these methods with the known, commercially-available apparatuses. Moreover, the commercially-available apparatuses are designed for a maximum of four parallel syntheses, so that a large number of parallel syntheses, as required for primer-walking sequencing, for example, can only be performed in small work segments, with reloading of the apparatus during the work time, but not, for example, overnight.
From DE 38 13 671 A1 device of the type mentioned at the outset is known, which comprises a stack of superposed reaction plates that can be displaced selectively and incrementally relative to one another, and are provided with passages disposed linearly with incremental spacing, of which one is respectively configured as a reaction chamber. A vertically and a horizontally traveling plate-adjusting device serves in selective displacement of the respective plate relative to the rest of the plate stack. The liquid-tight seal is effected by means of O-rings which encompass the passages and are placed in grooves. Each plate includes a single reaction chamber; for n reactions to be carried out, (n+2) plates are necessary.
Because of the condition that a plate must be provided for each reaction chamber, the device becomes unnecessarily complicated, because each individual plate, with the exception of the first (bottommost) and the last (topmost), must be displaced separately. Hence, an expensive displacement device is required. Because the reagents must be conducted through the entire plate stack, a considerable stagnant volume results, particularly when many reactions are supposed to be carried out, and therefore many plates are required.
Corresponding devices that have rotating plates are known from EP 0 164 206 B1 and EP 0 181 491 A1.
Therefore, it is the object of the invention to propose a simpler device with the aid of which in principle a virtually unlimited number of chemical reactions of the type of series of experiments mentioned above can be carried out simultaneously or sequentially. In comparison to the known apparatuses, the device should be able to be operated with smaller substance quantities. Moreover, the device is intended to be designed such that it can be controlled automatically.